CN105171728A - Hexagonal pyramid type six-freedom-degree parallel mechanism - Google Patents

Abstract

The invention relates to a motion simulation equipment, in particular to a hexagonal pyramid six-degree-of-freedom parallel mechanism. It consists of a load platform (1), a mechanism base (8) and six groups of branch chains connected in parallel. Each set of branch chains is composed of a Hooke hinge (2), a connecting rod (3), a three-degree-of-freedom hinge (4) and a linear motor (7). One end of the connecting rod (3) is connected with the load platform (1) through the Hooke hinge (2), and the other end is connected with the wedge-shaped slider (16) of the linear motor (7) through the three-degree-of-freedom hinge (4). The linear motor (7) drives the connecting rod (3) through the wedge-shaped slider (16) to drive the load platform (1) for linkage. The invention has the advantages of high speed, high precision, fast response, etc., the maximum rotation angle θ of the load platform (1) can reach 51°, and realizes six-degree-of-freedom vibration simulation of automobiles under off-road conditions.

Description

A Hexagonal Pyramid Six Degrees of Freedom Parallel Mechanism

technical field

The invention relates to motion simulation equipment, in particular to a hexagonal pyramid six-degree-of-freedom parallel mechanism driven by a linear motor and inclined with guide rails, which is suitable for vibration simulation on six degrees of freedom when a car is running on off-road conditions.

Background technique

At present, the known six-degree-of-freedom parallel mechanism consists of a load platform, a connecting rod, a base, a hinge and a drive system. Six connecting rods connect the load platform and the base through hinges. When the drive system changes the position or length of the connecting rods, the load platform can complete the expected six-degree-of-freedom movement in space. As one of the most widely used six-degree-of-freedom parallel mechanisms, motion simulators have become a research hotspot in recent years. Parallel mechanisms with different structures and different driving sources have different performance characteristics. When simulating the vibration of a car in six degrees of freedom under off-road conditions, the load platform is required to have better rotation performance (usually the maximum rotation angle θ>30°), but the existing six degrees of freedom parallel mechanism, such as Stewart For the platform, the driving source is usually attached to the kinematic link. The kinematic link is fixed on the same horizontal plane and is connected by a ball joint with a rotation angle range of less than 30°, resulting in a maximum rotation angle θ<10° between the load platform and the horizontal plane, which cannot meet the requirements. Simulation of vehicle six-degree-of-freedom vibration in off-road conditions.

The existing six-degree-of-freedom parallel mechanism usually adopts a mechanical-hydraulic drive system. The complex structure of the mechanism, the hysteresis of the elastic element and the expansion and contraction of the rod will all affect the performance of the mechanism. As an automobile six-degree-of-freedom vibration simulator, the mechanism should have the characteristics of high speed, high precision and fast frequency response, so the electro-hydraulic servo system has begun to be used in automobile six-degree-of-freedom vibration simulation. Electro-hydraulic control has the advantages of accurate, fast, and reliable signal transmission, and is easy to realize comprehensive adjustment and intelligent control of multiple adjustment parameters. However, it has not fundamentally solved the shortcomings of the hydraulic drive system, such as complex structure, low speed accuracy, and slow frequency response.

Contents of the invention

The technical problem to be solved by the present invention is to provide a hexagonal pyramid six-degree-of-freedom parallel mechanism to overcome the above-mentioned deficiencies in the prior art. Driven by a linear motor, it solves the problems of complex structure of the hydraulic drive system, prone to oil leakage and pressure relief faults, hysteresis of elastic elements, low movement speed and precision. The mechanism has better rotation performance and can meet the requirements of large rotation angle, high speed and high precision required for six-degree-of-freedom vibration simulation of vehicles under off-road conditions.

The technical solution adopted by the present invention to solve the technical problem is that it is composed of a load platform (1), a mechanism base (8) and six sets of branch chains, and the load platform (1) and the mechanism base (8) are connected by six sets of branch chains. Parallel connection is characterized in that: six groups of branch chains are arranged in a spoke type, and each group of branch chains is uniformly distributed at α=30° and β=90°, so that the load platform (1), mechanism base (8) and six groups The branch chains are arranged in a hexagonal pyramid shape; each group of branch chains is composed of a Hooke hinge (2), a connecting rod (3), a three-degree-of-freedom hinge (4) and a linear motor (7), and the linear motor (7) It is fixed on the mechanism base (8) in a tilted manner; the linear motor (7) is provided with a motor mover shaft (13) and a wedge-shaped slider (16) that can reciprocate and linearly move on the motor mover shaft (13); The upper end of the rod (3) is connected with the load platform (1) through the Hooke hinge (2); the lower end of the connecting rod (3) is connected with the wedge-shaped slide on the motor shaft (13) through the three-degree-of-freedom hinge (4). Block (16) is connected.

The linear motor (7) includes a motor central shaft (12), a motor magnet (19), a motor mover (20), a motor mover shaft (13), a motor casing (18) and a motor end cover (17) , the motor mover shaft (13) is set parallel to the motor center shaft (12); the motor magnet (19) is set on the motor center shaft (12), and the motor mover (20) is set on the outside of the motor magnet (19) , the motor mover (20) is connected to the wedge-shaped slider (16) on the motor mover shaft (13) through the connecting block (14), and the motor mover (20) is electromagnetically acted by the motor magnet (19) , to drive the wedge-shaped slider (16) to make a reciprocating linear motion along the motor rotor shaft (13).

The inclination angle between the motor mover shaft (13) of the linear motor (7) and the mechanism base (8) is set at δ=45°, and the motor mover shafts (13) of each group of branch chains are also set at 30° and 90° setting.

The Hooke hinge (2) comprises a pair of fork-shaped Hooke hinge end caps (24) and cross shafts (26), the four ends of the cross shaft (26) are provided with Hooke hinge bearings (25), two tiger hinges The gram hinged end caps (24) are connected by a cross shaft (26).

The three-degree-of-freedom hinge (4) includes a pair of fork-shaped three-degree-of-freedom hinge end covers (23), a cross shaft (26), a hinge bearing (27), a rotating pair top cover (28) and a rotating pair bearing (29 ), the four ends of the cross shaft (26) are provided with hinge bearings (27), and the two fork-shaped three-degree-of-freedom hinge end covers (23) are connected through the cross shaft (26); one of the three-degree-of-freedom hinge end covers (23) is fixedly connected with the wedge-shaped slider (16), and the other three-degree-of-freedom hinge end cover (23) is connected with the connecting rod (3) through the fixed rotating pair top cover (28) and rotating pair bearing (29); The connecting rod (3) can rotate in the rotating pair bearing (29), and can swing back and forth, left and right with the cross shaft (26).

The drive of the linear motor (7) adopts a single-chip microcomputer to realize the double closed-loop control of displacement and current.

The linear motor (7) is fixed on the mechanism base (8) through the linear motor base (6), and the angle between the linear motor base (6) and the mechanism base (8) is γ=45°.

Compared with the prior art, the present invention has the beneficial effects of:

(1) Both ends of the six sets of branch chains are connected and driven by Hooke hinges and three-degree-of-freedom hinges. At the same time, the linear motor adopts the inclined guide rail arrangement, so that the whole mechanism has extremely good rotation performance, and the maximum rotation angle of the load platform θ can reach 51°, which can meet the six-degree-of-freedom motion simulation of the car under off-road conditions (rotation angle > 30°);

(2) Compared with the traditional hydraulic drive, the linear motor drive method has the advantages of high speed, high precision, and fast response, and is more suitable as a drive system for vehicle vibration simulation;

(3) It adopts hexagonal pyramid and wheel-spoke parallel structure, which has the advantages of good rigidity, simple structure and small cumulative error.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the position structure schematic diagram of six branch chains;

Fig. 3 is a schematic diagram of the assembly of the mechanism base plate 8 and the motor base 6 in the section A-A in Fig. 2;

Fig. 4 is the structural representation of single branch;

Fig. 5 is the structural representation of linear motor 7;

Fig. 6 is the B-B sectional view of Fig. 5;

Fig. 7 is the C direction view in Fig. 5;

Fig. 8 is the D direction view among Fig. 5;

Figure 9 is the The partial enlarged view of is also the structural schematic diagram of the Hooke hinge 2;

Fig. 10 is the E-E sectional view of Fig. 9;

Fig. 11 is the F-F sectional view of Fig. 9;

Figure 12 is the The partial enlarged view of is also the structural schematic diagram of the three-degree-of-freedom hinge 4;

Fig. 13 is a G-G sectional view in Fig. 12 .

In the figure: 1. Load platform; 2. Hooke hinge; 3. Connecting rod; 4. Three-degree-of-freedom hinge; 5. Wedge slider; 6. Linear motor base; 7. Linear motor; 8. Mechanism base; 9. Locating pin; 10, bolt; 11, lock nut; 12, motor central shaft; 13, motor mover shaft; 14, connecting block; 15, linear bearing; 16, wedge-shaped slider; 17, motor end cover; 18, Motor shell; 19. Motor magnetic steel; 20. Motor mover; 21. Countersunk head screw; 22. Bolt; 23. Three-degree-of-freedom hinge end cover; 24. Hooke hinge end cover; 25. Hooke hinge bearing; 26 , cross shaft; 27, three-degree-of-freedom hinge bearing; 28, rotating pair top cover; 29, rotating pair bearing.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

The invention mainly consists of a load platform (1), a mechanism base (8) and six sets of branch chains, and the load platform (1) and the mechanism base (8) are connected in parallel through six sets of branch chains. Six groups of branched chains are arranged in the spoke type, and each group of branched chains is uniformly distributed at α=30° and β=90°, so that the load platform (1), the mechanism base (8) and the six groups of branched chains form a hexagonal pyramid shape settings.

Each set of branch chains is composed of a Hooke hinge (2), a connecting rod (3), a three-degree-of-freedom hinge (4) and a linear motor (7), and the linear motor (7) is obliquely fixed on the mechanism base (8) ;The linear motor (7) is provided with a motor mover shaft (13) and a wedge-shaped slider (16) that can reciprocate and linearly move on the motor mover shaft (13); the upper end of the connecting rod (3) passes through the Hooke hinge (2) Connected with the load platform (1); the lower end of the connecting rod (3) is connected with the wedge-shaped slider (16) on the motor rotor shaft (13) through a three-degree-of-freedom hinge (4).

The linear motor (7) includes a motor central shaft (12), a motor magnet (19), a motor mover (20), a motor mover shaft (13), a motor casing (18) and a motor end cover (17) , the motor mover shaft (13) is set parallel to the motor center shaft (12); the motor magnet (19) is set on the motor center shaft (12), and the motor mover (20) is set on the outside of the motor magnet (19) , the motor mover (20) is connected to the wedge-shaped slider (16) on the motor mover shaft (13) through the connecting block (14), and the wedge-shaped slider (16) is provided with a linear bearing (15). The sub (20) drives the wedge-shaped slide block (16) to do reciprocating linear motion along the motor rotor shaft (13) under the electromagnetic action of the motor magnet (19). The inclination angle between the motor mover shaft (13) of the linear motor (7) and the mechanism base (8) is set at δ=45°, and the motor mover shafts (13) of each group of branch chains are also set at 30° and 90° setting. The linear motor (7) is fixed on the mechanism base (8) through the linear motor base (6), and the angle between the linear motor base (6) and the mechanism base (8) is γ=45°. Wherein the motor end cover (17) is connected with the motor casing (18) through M3 countersunk screws (21). The wedge-shaped slider (5) is connected with the motor mover (20) through the connecting block (14) and the M3 bolt (22), and the wedge-shaped slider (5) is realized on the motor mover shaft (13) through the linear bearing (15). Reciprocating linear motion.

The Hooke hinge (2) comprises a pair of fork-shaped Hooke hinge end caps (24) and cross shafts (26), the four ends of the cross shaft (26) are provided with Hooke hinge bearings (25), two tiger hinges The gram hinged end caps (24) are connected by a cross shaft (26).

The three-degree-of-freedom hinge (4) consists of a pair of fork-shaped three-degree-of-freedom hinge end covers (23), a cross shaft (26), a hinge bearing (27), a rotating pair top cover (28) and a rotating pair bearing (29 ), the four ends of the cross shaft (26) are provided with hinge bearings (27), and the two fork-shaped three-degree-of-freedom hinge end covers (23) are connected through the cross shaft (26); one of the three-degree-of-freedom hinge ends The cover (23) is connected with the wedge-shaped slider (16) through M3 bolts (22), and the other three-degree-of-freedom hinge end cover (23) is connected with the rotating sub-top cover (28) through M3 bolts (22), and the rotating sub-top cover (28) is then connected with the interference fit of the rotating pair bearing (29) and the connecting rod (3). The connecting rod (3) can rotate in the rotating pair bearing (29), and can swing back and forth, left and right with the cross shaft (26).

The present invention has 6 branch chains in total. On each branch chain, one end of the connecting rod (3) is connected with the Hooke hinge (2) through the M3 bolt (22), and the other end of the connecting rod (3) is connected through the rotating pair bearing (29 ) is interference-connected with the three-degree-of-freedom hinge (4). The structure of the whole machine of the present invention is called a hexagonal pyramid parallel mechanism because it is arranged in a pyramid shape.

When the present invention is installed, the hub-and-spoke arrangement is adopted, and the linear motor base (6) at an included angle γ=45° is sequentially passed through the positioning pin (9) and the M10 bolt ( 10) Fixed on the mechanism base (8), the linear motor (7) is connected with the linear motor base (6) through the lock nut (11), the central shaft of the linear motor (12), and the mover shaft of the linear motor (13) to ensure The inclination angle of the two shafts of the linear motor is δ=45°.

When the present invention works, the position of the hinge on the guide rail of the linear motor (7) is changed through the driving system, and then the load platform is jointly driven by six connecting rods (3) to realize the movement in six degrees of freedom. Different from the traditional spherical hinge connection, the present invention adopts Hooke hinge and three-degree-of-freedom hinge for connection and transmission. The advantage is that the maximum rotation angle can reach 90°, so the present invention has better rotational performance. The load platform (1) The maximum rotation angle θ can reach 51°, which can meet the simulation of vehicle six-degree-of-freedom vibration under off-road conditions.

The control system uses a linear motor as an actuator, and the sensors involved include a displacement sensor and a current sensor. The double closed-loop control of displacement and current is realized through a single-chip microcomputer, thereby improving the control accuracy of the drive system and ensuring high speed and high speed when the mechanism moves. Precision, high response frequency.

The working principle of the present invention is: for a given load platform (1) motion law, the motion law of each linear motor is calculated by the mathematical model, including the change law of displacement, speed, acceleration and driving force, and the displacement and current of the single-chip microcomputer The double closed-loop control makes the linear motor (7) move according to the expected law. The motor mover (20) drives the wedge-shaped slider (16) to reciprocate along the linear motor mover shaft (13) through the connecting block (14), and the wedge-shaped slider (16) pushes the three-degree-of-freedom hinge (4), connecting rod (3 ) and Hooke hinges (2) move in six degrees of freedom in space, and the six Hooke hinges (2) act on the load platform (1) together, so that there is a unique load platform ( 1) The pose corresponds to it, realizing the six-degree-of-freedom movement of the load platform.

The hexagonal pyramid parallel mechanism has good rotation performance, the maximum rotation angle θ of the load platform (1) can reach 51°, and has the characteristics of high speed, high precision, fast response, etc., and can meet the needs of vehicles under off-road conditions. Simulation of degrees of freedom vibration.

Claims (7)

1. A hexagonal pyramid six-degree-of-freedom parallel mechanism, consisting of a load platform (1), a mechanism base (8) and six sets of branch chains, and six sets of branch chains pass between the load platform (1) and the mechanism base (8) Parallel connection is characterized in that: six groups of branch chains are arranged in a spoke type, and each group of branch chains is uniformly distributed at α=30° and β=90°, so that the load platform (1), mechanism base (8) and six groups The branch chains are arranged in a hexagonal pyramid shape; each group of branch chains is composed of a Hooke hinge (2), a connecting rod (3), a three-degree-of-freedom hinge (4) and a linear motor (7), and the linear motor (7) It is fixed on the mechanism base (8) in a tilted manner; the linear motor (7) is provided with a motor mover shaft (13) and a wedge-shaped slider (16) that can reciprocate and linearly move on the motor mover shaft (13); The upper end of the rod (3) is connected with the load platform (1) through the Hooke hinge (2); the lower end of the connecting rod (3) is connected with the wedge-shaped slide on the motor shaft (13) through the three-degree-of-freedom hinge (4). Block (16) is connected. 2. A hexagonal pyramid six-degree-of-freedom parallel mechanism according to claim 1, characterized in that: the linear motor (7) includes a motor central shaft (12), a motor magnet (19), and a motor mover (20), the motor mover shaft (13), the motor casing (18) and the motor end cover (17), the motor mover shaft (13) is set parallel to the motor center shaft (12); the motor magnet (19) is set on On the central shaft (12) of the motor, the motor mover (20) is sleeved on the outside of the motor magnet (19), and the motor mover (20) connects with the wedge-shaped The sliders (16) are connected, and the motor mover (20) drives the wedge-shaped slider (16) to reciprocate linearly along the motor mover shaft (13) under the electromagnetic action of the motor magnet (19). 3. A hexagonal pyramid six-degree-of-freedom parallel mechanism according to claim 1 or 2, characterized in that: the inclination angle between the motor rotor shaft (13) of the linear motor (7) and the mechanism base (8) δ=45° is set, and the motor mover shafts (13) of each group of branch chains are also set at 30° and 90° in turn. 4. A hexagonal pyramid six-degree-of-freedom parallel mechanism according to claim 1 or 2, characterized in that: the Hooke hinge (2) includes a pair of fork-shaped Hooke hinge end caps (24) and a cross Axle (26), the four ends of cross shaft (26) are provided with Hooke hinge bearing (25), are connected by cross shaft (26) between two Hooke hinge end caps (24). 5. A hexagonal pyramid six-degree-of-freedom parallel mechanism according to claim 1 or 2, characterized in that: the three-degree-of-freedom hinge (4) includes a pair of fork-shaped three-degree-of-freedom hinge end caps (23) , cross shaft (26), hinge bearing (27), rotating pair top cover (28) and rotating pair bearing (29), the four ends of cross shaft (26) are provided with hinge bearing (27), two fork-shaped three The hinge end caps (23) with degrees of freedom are connected by a cross shaft (26); one of the hinge end caps with three degrees of freedom (23) is fixedly connected with the wedge-shaped slider (16), and the other hinge end cap with three degrees of freedom (23) Connect with the connecting rod (3) through the fixed rotating pair top cover (28) and rotating pair bearing (29); ) swing back and forth, left and right. 6. A hexagonal pyramid six-degree-of-freedom parallel mechanism according to claim 1 or 2, characterized in that the linear motor (7) is driven by a single-chip microcomputer to realize double closed-loop control of displacement and current. 7. A hexagonal pyramid six-degree-of-freedom parallel mechanism according to claim 1 or 2, characterized in that the linear motor (7) is fixed on the mechanism base (8) through the linear motor base (6), and the linear motor base The angle between (6) and the mechanism base (8) is γ=45°.